Tory MPs warned that Theresa May was “one crisis from the exit” last night after the most shambolic conference speech in memory.

Recriminations were levelled at Boris Johnson and Sir Patrick McLoughlin, the Conservative Party chairman, after a prankster was allowed to hand a joke P45 to the prime minister during the speech before she suffered repeated coughing fits and lost her voice.

PM’s conference nightmare

During the hour-long address, which was designed to settle questions over whether Mrs May had the authority and resilience to carry on in No 10, letters also began to fall from the slogan behind her.

MPs blamed Mr Johnson, the foreign secretary, for heaping pressure on the prime minister with disloyal interventions over recent weeks. Sources from the party, which took events